More than a third of the population of Europe suffer from some sort of a mental disorder each year, according to a study which calls attention to the scale of the problem and the paucity of treatment.

The research from the European College of Neuropsychopharmacology has found that more than 164 million people in the EU – more than 38% of the population – have a mental disorder in any year.

The researchers include not only psychological problems such as depression, anxiety and insomnia, but also neurological illnesses, including Parkinson's disease and dementia.

"The numbers are immense," said Hans-Ulrich Wittchen, one of the authors. Anxiety disorders top the list: 14% of the EU population suffer from one or more of them each year, while 7% experience insomnia, 6.9% have depression and 5.4% suffer dementia.

The burden on countries in the EU is very similar, but there are gender differences. Men are more likely than women to become alcohol-dependent, while women suffer disproportionately from depression, which has increased markedly in the last four decades.

Depression hits women in greatest numbers between the ages of 16 and 42, said Wittchen. "We have seen, as compared to the 70s, a doubling of depressive episodes in females. It happened in the 80s and 90s. It is stable now but much higher than in the 70s and the time before."

It had been linked, he said, to changing social patterns: women were increasingly taking on marriage and a family as well as a job, and divorce was becoming more common. It tended to be those who felt they were not coping well with caring for their children who were driven into depression. Marriage, he added, was bad for women, although good for men.

He and his colleagues are concerned about the early onset of mental disorders. Where it used to be people in their 20s who were first diagnosed with anxiety, now it is people in their teens. Around 90% of anxiety disorders occur for the first time before the age of 18, he said. At that point – if they are detected – they can be easily treated. "You can fix two-thirds easily," he said. Usually, this would be with talking therapies but, if necessary, with the help of drugs as well. But if such conditions are left, they often recur and can be the precursors of depression and other brain disorders in later life.

He wants to see routine screening offered in schools – "as with dental care". Teachers and parents should be trained to recognise a child who may have a problem.

The study reveals a lack of treatment for mental disorders. Only 30-52% of European sufferers have any contact with a health professional and only 8-16% are in contact with a specialist. A tiny minority, 2-9%, "receive minimally adequate treatment", said Wittchen.

This is not the same for neurological disorders – 80% of people with multiple sclerosis get treatment, for instance – but inadequate research funding means that the treatments are not as good as they should be.

"It is very clear that there is a significant under-funding of research," said David Nutt, professor of neuropsychopharmacology at Imperial College London and a past president of the European college. His best estimate was that brain disorders, representing a third of the disease burden, received about one sixth of the main research funding available in the UK.

"We're under-funded by about 50% of what we should be," he said. "This is something that has to change. One of the big challenges is that if you can get in early, you may be able to change the trajectory so it is not inevitable that people go into disability."